scikit-learn/sklearn/utils/tests/test_encode.py

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import numpy as np
import pytest
from numpy.testing import assert_array_equal
from sklearn.utils._encode import _unique
from sklearn.utils._encode import _encode
from sklearn.utils._encode import _check_unknown
@pytest.mark.parametrize(
"values, expected",
[(np.array([2, 1, 3, 1, 3], dtype='int64'),
np.array([1, 2, 3], dtype='int64')),
(np.array(['b', 'a', 'c', 'a', 'c'], dtype=object),
np.array(['a', 'b', 'c'], dtype=object)),
(np.array(['b', 'a', 'c', 'a', 'c']),
np.array(['a', 'b', 'c']))],
ids=['int64', 'object', 'str'])
def test_encode_util(values, expected):
uniques = _unique(values)
assert_array_equal(uniques, expected)
encoded = _encode(values, uniques=uniques)
assert_array_equal(encoded, np.array([1, 0, 2, 0, 2]))
def test_encode_with_check_unknown():
# test for the check_unknown parameter of _encode()
uniques = np.array([1, 2, 3])
values = np.array([1, 2, 3, 4])
# Default is True, raise error
with pytest.raises(ValueError,
match='y contains previously unseen labels'):
_encode(values, uniques=uniques, check_unknown=True)
# dont raise error if False
_encode(values, uniques=uniques, check_unknown=False)
# parameter is ignored for object dtype
uniques = np.array(['a', 'b', 'c'], dtype=object)
values = np.array(['a', 'b', 'c', 'd'], dtype=object)
with pytest.raises(ValueError,
match='y contains previously unseen labels'):
_encode(values, uniques=uniques, check_unknown=False)
@pytest.mark.parametrize("values, uniques, expected_diff, expected_mask", [
(np.array([1, 2, 3, 4]),
np.array([1, 2, 3]),
[4],
[True, True, True, False]),
(np.array([2, 1, 4, 5]),
np.array([2, 5, 1]),
[4],
[True, True, False, True]),
(np.array(['a', 'b', 'c', 'd'], dtype=object),
np.array(['a', 'b', 'c'], dtype=object),
np.array(['d'], dtype=object),
[True, True, True, False]),
(np.array(['d', 'c', 'a', 'b'], dtype=object),
np.array(['a', 'c', 'b'], dtype=object),
np.array(['d'], dtype=object),
[False, True, True, True])
])
def test_check_unknown(values, uniques, expected_diff, expected_mask):
diff = _check_unknown(values, uniques)
assert_array_equal(diff, expected_diff)
diff, valid_mask = _check_unknown(values, uniques, return_mask=True)
assert_array_equal(diff, expected_diff)
assert_array_equal(valid_mask, expected_mask)